Apparatus for automatically binding the neck of a bag



Jan. 20, 1970 CAMMlLLl ETAL 3,490,128

APPARATUS FOR AUTOMLKTICALLY BINDING THE NECK OF A BAG Filed Sept. 18, 1967 5 Sheets-Sheet l w m E V W REA/A70 CAMM/LL/ BY P055270 @IAN/VELL/ Jan. 20, 1970 AMM|LL| ETAL 3,490,128

APPARATUS FOR AUTOMATICALLY BINDING THE NECK OF A BAG Filed Sept. 18, 1967 3 Sheets-Sheet 2 Fag 3 INVENTORS H a. 4; ea /Wm CAM/WILL! Y eoamro amwau ATTOEIVEVF Jan. 20, R AMM ET AL APPARATUS FOR AUTOMATICALLY BINDING THE NECK OF A BAG Filed Sept. 18, 1967 5 Sheets-Sheet 5 INVENTORS REA/A 7'0 CA MM/l-l-l ROBE? T0 GIANNE'LLI drive/vars United States Patent U.S. Cl. 29-208 14 Claims ABSTRACT OF THE DISCLOSURE Apparatus for automatically binding the neck of a bag, by spirally twisting together the ends of a coated metal core thread extending around the bag neck, is disclosed as including a support formed with a relatively elongated slot or opening arranged to receive the folded neck of a bag. At one side of this opening, a pincer means is reciprocably mounted and includes a pair of apertured and pivoted jaws arranged to hold a length of thread therebetween. Thread twisting means are rotatably mounted adjacent the opposite side of said opening in alignment with the pincer means. Feeding means are provided for drawing thread from a spool rotatably mounted on the support and feeding a preselected length of thread through the jaws of the pincer means. Shearing means then severs such preselected length, and the pincer means is advanced across the opening in the support to draw the length of thread around the neck of the bag. As the pincer means overlaps the twisting means, guide means engage the jaws to close the same to draw the ends of the thread into engagement with the twisting means. The twisting means then rotates to twist together the ends of the thread length to bind the neck of the bag.

An electric motor is energized responsive to insertion of the neck of a bag into the receiving opening, and drives a main shaft carrying cam and gear means for operating the thread feeding means, thread shearing means, pincer means and thread twisting means in a predetermined and repetitive cycle.

BACKGROUND OF THE INVENTION An arrangement frequently used for binding the necks of filled or partially filled bags, particularly relatively small bags, involves bending a length of wire or a length of a coated metal core thread around the neck of the bag and then twisting the ends of the wire length or thread length together. This is generally effected manually, or at best, semi-automatically, and uniformity of the binding ties is not only difficult to obtain but is also problematical. Accordingly, there is a need for an apparatus that will automatically effect this type of binding of the neck of a filled or partially filled bag, in a uniform manner and with consistently reproducible results, :as well as expediting the operation of binding the necks of such bags.

SUMMARY OF THE INVENTION This invention relates to the binding of necks of filled or partially filled bags and, more particularly, to a completely automatic, electric motor operated mechanism for effecting such binding and having a high output.

In accordance with the invention, a support is provided in the form of a relatively flat plate having an inwardly tapering notch or opening in one edge arranged to have the folded neck of a bag inserted therein. Adjacent one side of this notch or open-ing, a pincer means is mounted for reciprocation across the opening and includes a pair of apertured and pivoted jaws arranged to hold a length "ice of thread, such as a coated metal core thread, therebetween. Adjacent the opposite side of this opening, thread twisting means are rotatably mounted for rotation about an axis aligned with the direction of reciprocation of the pincer means. A spindle on the support rotatably supports a spool of the coated metal core thread, and feeding means are provided to withdraw thread from this spool and to feed a preselected length thereof through the jaws. Between the feeding means and the jaws there is a shearing means operable to sever the preselected length of thread from the thread still attached to the spool.

An electric motor is provided in driving engagement with the main shaft, and this electric motor is energized responsive to insertion of the folded neck of a bag into the opening or slot. The motor then rotates the main shaft which carries cam means and gear means operable to operate the feeding means, shearing means, pincer means and twisting means in a predetermined cycle. At the end of the cycle, the motor is de-energized and the several means remain in a preset at rest position.

In the first step of the cycle, one of a pair of rotatable feeding wheels is turned through a predetermined angle to draw the thread through a guide tube and feed it past the shearing means into the jaws of the pincer means. This operation is effected by a cam means driven by the main shaft.

In the next step, a movable element of the shear means is advanced to sever the preselected length of thread, and this operation is effected by gear and cam means operated from the main shaft. Cam and lever means, also operated by the main shaft, then advance the pincer means across the bag neck receiving opening or slot to bend the preselected length of thread around the neck 'of the bag, and to bring the ends of the thread length into operative relation with the twisting means. At this time, guide means engage the pincer jaws to close the same together to displace the thread ends laterally toward the twisting means. The twisting means is then rotated a predetermined number of times by a cam, gear and chain drive means operated from the main shaft, and spirally twists together the ends of the thread extending around the bag neck. The operation is then terminated with all parts being retracted to the at rest position, with the motor being de-energized, its shaft braked, and the spool of thread braked.

An object of the invention is to provide apparatus for automatically binding the neck of a filled or partially filled bag by spirally twisting together the ends of a coated metal core thread extending around the bag neck.

Another object of the invention is to provide such an apparatus which has a high output and is simple in construction.

A further object of the invention is to provide such apparatus which performs a predetermined cycle of operations responsive to insertion of the neck of a filled or partially filled bag into a slot in a support.

Still another object of the invention is to provide such an apparatus in which all of the several elements are cyclically operated by cam, gear and lever means driven by a main shaft connected by a transmission to an electric motor, which motor is energized responsive to insertion of a bag neck into a slot on a support. A further object of the invention is to provide such an apparatus for feeding preselected lengths of a thread, such as a coated metal core thread, to pincer means which, in turn, wrap the length of thread around the neck of the bag and deliver the ends to twisting means which spirally twist together the ends of the thread length.

Yet another object of the invention is to provide such an apparatus in which the lengths of the thread fed to the pincer means can be varied in accordance with the particular operation to be performed.

3 BRIEF DESCRIPTION OF THE DRAWINGS For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompzfnying drawings.

In the drawings:

FIG. 1 is a top plan view of apparatus embodying the invention;

FIG. 2 is a bottom plan view of a portion of the apparatus;

FIG. 3 is an elevation view illustrating a spool holder with associated braking and thread drawing devices;

FIG. 4 is a partial plan view illustrating the thread twisting unit;

FIG. 4A is a partial elevation view illustrating the thread twisting means as viewed from the left in FIG. 4;

FIG. 5 is an inverted partial elevation view of the unit controlling operation of the thread feeding means;

FIG. 5A is a view,, looking from the right as viewed in FIG. 5, of a control disk forming part of the unit shown in FIG. 5; and

FIG. 5B is a view, looking from the left in FIG. 5, of a gear member forming part of the unit shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1 and 2, the arrangement includes a base or support 7, which is generally rectangular, and has an extension 7a at one end. Supported on the base 7 in vertically spaced relation thereto is a second support plate 712 which mounts substantially all the operative units of the apparatus except the thread spool and the braking means associated therewith.

Mounted on the extension 7a is a circular rimmed disk or plate 1 having a spindle 2 extending centrally outwardly therefrom and rotatably supporting a spool of thread 1a. The spool 1a is mounted loosely on the spindle 2 so that it may rotate freely for withdrawal of coated metal core thread 3 therefrom. An arm 6 is fixed to extension 7a to extend radially with respect to spindle 2 and projects beyond the disk 1. A bent brake lever 4a is pivotally mounted, intermediate its ends, on arm 6 and carries, at one end, a brake shoe 4 engageable with a rim of spool 1a. The other end of brake lever 4a carries a thread guide means including a roller 4b, and a tension spring 5 is connected between brake lever 4a and arm 6 and normally tends to bias brake shoe 4 into braking engagement with the rim of spool 1a. However, when thread 3 is under tension, lever 4a is swung counterclockwise, as viewed in FIG. 1, to disengage brake shoe 4 from spool 1a.

Beyond roller 4b, thread 3 is engaged with a roller 8b on one end of a thread control lever 8 pivoted, intermediate its ends, at 8a on the support structure. For a purpose to be described, lever 8 has a shorter bent end 8c engaging a lever 9 pivoted at 9a on the support structure. One end of lever 9 is pivotally connected at 12 to a link pivotally connected at 13 to an end of a lever 11 pivoted, intermediate its ends, at a pivot 11a of the support structure.

The free end of lever 11 carries a rotatable bearing or follower member 14 which is biased into engagement witha cam 15 by a tension spring 16. Cam 15 is a face cam mounted on a coaxial plate 15a so that the variable thickness of cam 15 controls displacement of follower 14 and thus of lever 1.1. The duration of contact of roller 14 with cam 15 is determined by the angular extent of cam.15. It will be appreciated that the thickness and angular extent of cam 15 may be varied in accordance with the particular parameters of the operation to be performed.

As best seen in'FIG. 2, cam 15 is fixedly secured to a main shaft 17 rotatably mounted on the support structure and driven by an electric motor 18, also mounted on the support structure, through a transmission or re duction gear means generally indicated at 18a. The final element of the transmission means or reduction gearing is a spur gear 39 mentioned more specifically hereinafter. A disk or gear means 19 is also fixedly secured to shaft 17 in axially spaced relation to a disk 20 likewise fixedly secured to shaft 17. Gear means 19 interchangeably carries a bevelled gear sector 19a having a preselected angular extent and arranged to mesh with a bevel gear 21 secured on one end of a shaft 22 rotatably mounted in the structure 7b. The other end of shaft 22 has fixed thereto a disk or wheel 23 whose peripheral surface is advantageously covered with rubber or similar friction material.

Referring to FIG. 5, a diametrically extending groove 21a is formed across the smaller base of pinion 21, and is arranged to be engaged by disk 20. However, it will be noted that disk 20 has an arcuate recess portion 20a whose angular extent is substantially equal to the angular extent of bevel gear segment 19a. When this arcuate recess 20a is aligned with bevel gear 21, the latter is free to be rotated by the gear segment 19a but, at the end of such rotation, the larger diameter portion of disk 20 enters into the diametrically extending groove 21a to lock gear 21, shaft 22 and disk or wheel 23 against rotation. At this time, gear segment 19a will have moved out of engagement with pinion 21.

The electric motor 18 is energized responsive to insertion of the neck 24 of a bag into the receiving slot 25 formed in one end of the support portion 7b. This slot tapers inwardly and is relatively elongated, and when the neck of the bag, which has been appropriately folded, is introduced into slot or opening 25, it engages a lever 26 pivoted at 260 on the support structure and having a free end pivotally connected, at 260, to one end of a rod 27. This moves rod 27 downwardly, as viewed in FIG. 2, so that a laterally extending end 27a thereof engages and rotates a cam 28 which is freely rotatable on shaft 17. Cam 28 is appropriately shaped to close a switch 29 controlling connection of motor 18 to a source of potential. A spring 30 is operatively connected with cam 28 to return the same to a switch opening position upon withdrawal of the neck of a bag from slot or opening 25.

Referring again to FIG. 1, a wheel 31 is rotatably mounted on the free end of an arm 32 and on a slide 3111 slidably engaged in a transverse rectangular slot 31b in such manner that wheel 31 acts in opposition to the aforementioned wheel 23. Arm 32 is pivoted to the support structure at a pivot 32a, and a tension spring 33 connected between arm 32 and the support structure biases wheel 31 toward wheel 23. The thread 3, after passing over the roller 8b, passes around a circular guide 34, rotatably mounted on support structure 7b, and through a thread guide and straightening tube 35 which directs the thread into the nip between wheels 23 and 31.

Wheels 23 and 31 cooperatively feed the straightened thread 3 through a fixed part 36 of a shears having a movable part 37 cooperable with fixed part 36. Movable shears part 37 is moved in a thread shearing direction by a face cam 38 on the aforementioned spur gear 39 fixed to shaft 17, and a spring 37a biases part 37 of the shears to the retracted position. In advance of the shearing action, the thread will have been fed through apertures 40a near the outer ends of pivoted jaws 40b of a pincer means 40. A spring 400 biases jaws 40b to the spread apart position. After the operation of shears 36-37, a segment 3a of thread 3 remains held in apertures 40a.

Pincer means 40 is slidably reciprocable on support 5 Thereby, upon oscillation of lever 9 under the control of lever 11, follower 14 and cam 15, rod 40e of the pincer means 40 is reciprocated transversely of the support means. It will be noted that pincer means 40 is located to one side of the slot or opening 25.

A twisting means, generally indicated at T, is located adjacent the opposite side of slot or opening 25 and includes a shaft 42 mounted for rotation about an axis which is aligned with the rod 40:? f pincer means 40. As pincer means 40 is advanced toward twisting means T, the severed segment 3a of thread 3 is wrapped around neck 24 of the bag to form a bight engaged with the neck 24 and ends extending from the bight. The arms 40b of pincers 40 then engage the guide means or guide horns 41 which swing the arms 40b toward each other and this brings the ends of the segment 3a into proximity with hooks 43 on the end of rotatable shaft 42. The hooks 43 are appropriately shaped to catch the ends of thread segment 3a and to spirally twist the ends together thereby binding the neck 24 of the bag in a perfectly tied fashion. FIG. 1 illustrates the pincer means 40 and the twisting means T in their relatively disengaged position, whereas FIGS. 4 and 4A illustrate the parts when the hooks 43 are engaging the ends of the thread segment 3a.

Shaft 42 is driven by main shaft 17 through the medium of a circular disk 44 carrying, on its periphery and through a relatively small angular extent thereof, a gear segment 44b. Disk 44 is fixed to shaft 17, and has fixed thereto a relatively thin disk-shaped flange 44a which has a chordal peripheral portion substantially snbtending the arc of the gear segment 44b. A chain sprocket 42a is secured to the outer end of shaft 42 and connected by an endless chain 45 to a chain sprocket 46b to which is secured a pinion 46. A cam disk 46a is secured coaxially to pinion 46 and is in the form of a relatively fat crescent, cam disk 46a being of much smaller diameter than disk flange 44a. The larger radius curved portion of the crescent-shaped periphery of cam disk 46a has a curvature substantially conforming to the circularly curved portion of the periphery of disk flange 44a.

When gear segment 44b meshes with pinion 46, the chordal portion of the periphery of flange 44a is aligned with the cam disk 46a so that the later may rotate along with pinion 46, thus providing for rotation of shaft 42. As gear segment 44b disengages pinion 46, the curvilinear portion of the periphery of disk flange 44a comes into engagement with the larger radius arcuate surface of the crescent-shaped contour of cam disk 46a and thus lock cam disk 46a against rotation to arrest rotation of shaft 42 in a predetermined fixed position.

The operation of the apparatus will now be described. Before starting a tying apparatus, the thread 3 is withdrawn from the spool 1a, threaded around the thread guide means 5b, over the guide roller 8b and around the guide member 34 and into the straightening and guide tube 35. Wheel 31 is retracted from wheel 23, against the bias of spring 33 and the tread is advanced between the W'hCBlS 23 and 31 and through the stationary shears member 36. When the appropriately folded upright neck 24 of a filled or partially filled bag is introduced into the slot 25 to engage the lever 26, electric motor 18 is energized, as mentioned, through closure of switch 39, and rotates main shaft 17 through the reduction gearing 18a. This causes wheel 23 to be ro tated by disk 19, bevel gear segment 19a, bevel gear 21 and shaft 22 to advance, in cooperation with the counter wheel 31, a predetermined length of thread 3 into the apertures 40a of arms 40b of pincers 40. As bevel gear segment 19a disengages bevel gear 21 and the full diameter portion of disk 20 enters into slot 21a, to lock wheel 23 against rotation, the movable shears member 37 is projected by face cam 38 carried by spur gear 39, and severs thread 3 in cooperation with fixed shears member 36, to leave the thread portion 3a supported in arms 40b.

Cam 15 now displaces follower 14 and arm 11 so that, through link 10, arm 9 is swung counterclockwise, as viewed in FIG. 2, to advance pincers 40 to the right as viewed in FIG. 1 to wrap thread section 3a around the neck 24 of the bag and bring the ends of the thread section into a position where they can be caught by the hooks 43. At this time, gear segment 44b meshes with pinion 46 to rotate shaft 42 through chain drive 45 to twist the ends of the thread section 3a spirally around each other to form a perfect binding around the neck of the bag. As arm 9 swings counterclockwise, as viewed in FIG. 2, lever 8 is swung counterclockwise, also as viewed in FIG. 2, so that roller 8b is moved to the left, as viewed in FIG. 1, or clockwise, to tension thread 3 which is still clamped between stationary wheels 23 and 31, and thus release brake 4 from spool 1a and draw a length of thread from the spool. As arm 9 returns clockwise to retract pincers 40 to the position of FIG. 1, under the action of spring 15 in cooperation with the roller follower 14 engaging the cam 15, roller 8b is swung to the position of FIG. 1 which is its rest position. At the same time, pincers 40 reaches its rest position as shown 'in FIG. 1. This releases tension on the thread 3 so that brake 4 re-engages spool 1a to hold the spool stationary. The movable shears element 37 will previously have been retracted by spring 37a as the shaft 17, and thus gear 39, continue to rotate. As the tied bag neck is withdrawn from slot or opening 25, switch 29 is opened due to spring 30 returning cam 28 to its rest position and motor 18 is de-energized, with brake 47 immediately arresting rotation of the motor shaft. The cycle is then ready to be repeated upon insertion of another bag neck 24 into the opening 25 to engage the lever 26.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Apparatus for automatically binding the neck of a bag by spirally twisting together the ends of a coated metal core thread length extending around the bag neck, said apparatus comprising, in combination, a support formed with an opening for insertion of a bag neck thereinto; means rotatably supporting a spool of said thread on said support; pincer means reciprocably mounted adjacent one side of said opening and arranged to hold a length of said thread therebetween for transport across said opening and bending of said thread length around the neck of a bag in said opening; thread twisting means rotatably mounted adjacent the opposite side of said opening and arranged to engage the ends of a thread length bent around the neck of the bag to spirally twist together such ends to form a binding tightly closing the neck of the bag; feeding means operable to draw thread from the spool and feed a preselected length of thread into said pincer means; shear means operable to sever such preselected thread length; driving means on said support; a main shaft rotatably mounted on said support; transmission means connecting said driving means to said main shaft to rotate the latter; and cam means and gear means carried by said main shaft and operatively associated with said feeding means, said shear means, said pincer means, and said thread twisting means to cyclically and successively feed a preselected length of thread to said pincer means, sever such preselected thread length, advance said pincer means into operative relation with said thread twisting means, and rotate said thread twisting means to effect such spiral twisting together of the ends of a thread length extending around the bag neck.

2. Apparatus for automatically binding the neck of a bag, as claimed in claim 1, in which said driving means comprises an electric motor and a switch controlling connection of said motor to a source of electric potential; said bag receiving opening including means operable, responsive to insertion of the neck of a bag into said opening, to close said switch to energize said electric motor.

3. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said means included in said bag receiving opening comprises a pivoted lever engageable by the neck of a bag inserted into said opening, a cam freely rotatable on said main shaft and including a cam surface engageable with said switch, a link connecting a free end of said lever to said cam to rotate said cam responsive to swinging of said lever under the action of the neck of a bag inserted into said opening, and spring means biasing said cam to a position providing for opening of said switch.

4. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said thread feeding means comprises a thread engaging wheel rotatably mounted on said support and a bevel gear coaxial with said wheel and rotatable therewith, said bevel gear having a slot extending diametrically of one surface thereof; said gear means including a disk fixed to said main shaft and carrying a bevel gear segment on one face engageable with said bevel gear; said cam means including a circular disk fixed on said main shaft in axially spaced relation to said first mentioned disk and rotating in a plane extending diametrically of said bevel gear, said second mentioned disk being engageable in said diametric slot and having a recess in its periphery substantially coextensive with the arcuate extent of said bevel gear segment and aligned with said slot when said bevel gear segment is engaged with said bevel gear; the remainder of the periphery of said second mentioned disk entering said diametric slot upon disengagement of said bevel gear segment from said bevel gear to lock said thread engaging wheel against further rotation.

5. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said thread twisting means includes a rotatable shaft, a first chain sprocket secured to rotate with said shaft, a second chain sprocket spaced from said first chain sprocket, an endless chain interconnecting said sprockets, a pinion secured to rotate with said second chain sprocket and a first cam disk rotatable with said pinion; said gear means including a gear disk rotatable with said main shaft and carrying a spur gear segment engageable with said pinion; said cam means including a second cam disk secured to rotate with said gear disk and cooperable with said first cam disk; said second cam disk including a recessed peripheral portion substantially subtending the arc of said spur gear segment and positioned opposite said first cam disk when said spur segment is in mesh with said pinion; said first cam disk including a peripheral portion engageable with said second cam disk when said spur gear segment is out of mesh with said pinion and locking said pinion against rotation except when said spur gear segment meshes with said pinion.

6. Apparatus for automatically binding the neck of a bag, as claimed in claim 4, in which said thread feeding means includes a second wheel mounted on said support and means biasing said second Wheel toward said first mentioned wheel to grip the thread therebetween; said shear means being mounted beyond said first mentioned wheel and said second wheel in the direction of thread feed; said thread feeding means including a lever pivoted intermediate its ends on said support, a brake shoe on one end of said lever engageable with the rim of a spool rotatably supported on said support, a thread guide on the opposite end of said lever and a spring biasing said leverin a direction to engage said brake shoe with the spool; said thread feeding means further including a second lever pivotally mounted intermediate its ends on said support and carrying a second thread guide; the thread from the spool being threaded over said first thread guide and over said second thread guide before entering the nip between said wheels; said second lever normally occupying a position in which said second thread guide exerts substantially no tension on the thread length between said first thread guide and the nip of said wheels, whereby said brake shoe is biased into engagement with the rim of a spool; said cam means including a face cam fixed to rotate with said main shaft and cam follower means engaged with said face cam and operatively connected to said second lever; said face cam, during a part of the cycle, operating said cam follower means to swing said second lever to a position in which said second thread guide exerts suflicient tension on said thread and said first thread guide to disengage said brake shoe from the spool and to draw a length of thread from the spool and over said first thread guide to said second thread guide.

7. Apparatus for automatically binding the neck of a bag, as claimed in claim 6, in which said cam follower means includes a third lever pivoted intermediate its ends to said support, a cam follower on one end of said third lever, means biasing said third lever in a direction to maintain said cam follower engaged with said face cam, a fourth lever pivotally mounted intermediate its ends on said support and engaged with the free end of said second lever, and link means pivotally interconnecting the opposite end of said third lever to one end of said fourth lever; said pincer means including means connecting said pincer means to the opposite end of said fourth lever to effect reciprocation of said pincer means responsive to oscillation of said fourth lever; said fourth lever, upon oscillation in a direction to advance said 'pincer means toward said thread twisting means, swinging said second lever in a direction to tension the thread and withdraw thread from the spool.

8. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said cam means includes a face cam secured to rotate with said main shaft, a lever pivoted intermediate its ends on said support, cam follower means connected to one end of said lever and means biasing said cam follower means to continuously engage said face cam; said support being formed with a substantially rectilinear slot aligned with the direction of movement of said pincer means and said pincer means including a pin extending therefrom and engaged in said slot; the opposite end of said lever being formed with an elongated slot receiving said pin; whereby, upon oscillation of said lever by said face cam and said cam follower means, said pincer means is reciprocated across said bag neck receiving opening between a rest position and a working position, in the latter of which it is adjacent said twisting means.

9. Apparatus for automatically binding the neck of a bag, as claimed in claim 8, in which said thread feeding means includes a second wheel cooperable with said first mentioned wheel to grip a thread therebetween, means biasing said second wheel toward said first mentioned wheel to grip a thread therebetween, a second lever pivotally mounted intermediate its ends on said support, a brake shoe on one end of said second lever, means biasing said second lever in a direction to engage said brake shoe with the rim of a spool rotatably supported on said support, a first thread guide carried by the opposite end of said second lever, a third lever pivotally mounted intermediate its ends on said support; a second thread guide carried by one end of said third lever and positioned between said first thread guide and said wheels, the thread from the spool being trained over said first thread guide and said second thread guide before entering the nip between said wheels; said shear means being positioned beyond said wheels in the direction of thread advance; the opposite end of said third lever being engaged with said first mentioned lever and said third lever normally occupying a rest position in which said second thread guide exerts substantially no tension on the thread; said third lever being swung to a working position, upon movement of said first mentioned lever to advance said pincer means to its working position, and exerting tension on the thread between said first thread guide and said wheels to release said brake from the spool and to draw thread from the spool; said pincer means and said third lever reaching their respective working positions simultaneously and reaching their respective rest positions simultaneously under the action of said face cam and said cam follower means.

10. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said pincer means comprises a slide and a pair of jaws pivotally mounted on said slide and formed with aligned apertures adjacent their free ends to receive a length of thread therein, and means biasing said jaws to a spread apart position; said thread twisting means including a rotatable shaft and hook means carried on the end of said shaft facing said pincer means, and further including a pair of guiding horns engageable with said jaws, upon movement of said pincer means toward said thread twisting means, to close said jaws to bring the ends of a thread length, bent around the neck of a bag in the bag neck receiving opening, into engagement with said hook means for spiral twisting together of the ends of the thread length by said hook means.

11. Apparatus for automatically binding the neck of a bag, as claimed in claim 4, in which said pincer means is reciprocable between a working position, in which it is in operative relation with said thread twisting means, and a rest position; said bevel gear sector engaging said bevel gear to rotate said wheel when said pincer means is in the rest position, and said cam disk locking said bevel gear against rotation when said pincer means is moved to the working position and during return of said pincer means to the rest position.

12. Apparatus for automatically binding the neck of a bag, as claimed in claim 11, in which said shear means includes a stationary anvil disposed between said thread feeding means and said pincer means and a movable shears member cooperable with said stationary anvil to sever a length of thread advanced into said pincer means; said transmission means including a spur gear fixed to and driving said main shaft; said cam means including a face cam on said spur gear operatively engageable with said shears movable member to advance the same to sever the thread length; spring means biasing said shears movable member to a retracted position; said face cam on said spur gear operating said shears movable member to sever the thread length during the time period when said bevel gear is locked against rotation.

13. Apparatus for automatically binding the neck of a bag, as claimed in claim 10, in which said thread feeding means includes a thread straightening guide aligned with the apertures in said jaws; said shear means including an anvil having a thread receiving passage extending therethrough in alignment with said thread guide and the apertures in said jaws.

14. Apparatus for automatically binding the neck of a bag, as claimed in claim 2, in which said driving means further includes a brake engageable with the shaft of said electric motor to arrest rotation of said shaft upon de-energization of said electric motor.

References Cited UNITED STATES PATENTS 2,879,512 3/1959 Tipper. 3,173,456 3/1965 Bailey 140-1236 3,254,682 7/1966 Gelardi 140149 3,389,533 6/1968 Tipper et al. 53-134 THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 

